https://www.mercurynews.com/2021/10/25/covid-should-i-choose-moderna-pfizer-or-jj-for-my-vaccine-booster/

When the Centers for Disease Control and Prevention green-lighted mixing booster shot brands last week for the various COVID-19 vaccines, it said people who originally had one kind may choose another.

But is it better to mix or to match? And when you make an appointment or drop by your favorite drug store, will you really have your choice like it’s Coke, Pepsi or RC Cola? The CDC left those questions unanswered when it announced “eligible individuals may choose which vaccine they receive as a booster dose” and that the agency’s recommendations “now allow for this type of mix and match dosing.”